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recipe card image of the zucchini tomato casserole on a blue and white plate

Zucchini Tomato Casserole With Cheese and Herbs

Amber Bondar
This easy zucchini tomato casserole features layered fresh zucchini, ripe tomatoes, red onion, cheddar cheese, and parmesan. Baked to golden brown in a cast iron skillet or baking dish, it’s the perfect summer side dish for using up extra garden vegetables.
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Prep Time 10 minutes
Cook Time 30 minutes
Total Time 40 minutes
Course Side Dish
Cuisine American, Canadian
Servings 6
Calories 156 kcal

Equipment

Ingredients
  

  • 3 Medium Zucchini (Yellow or Green) Sliced Thinly
  • 2 Large Tomatoes Sliced Thinly
  • 1 Large Red Onion Sliced Thinly In Rings
  • 1 tsp Black Pepper
  • 1 Tbsp Italian Seasoning
  • 1 Cup Shredded Cheddar Cheese
  • ½ Cup Parmesan Cheese
  • 5 Tbsp Olive oil

Instructions
 

  • Preheat oven to 350°F (175°C).
  • Slice the zucchini with a mandolin slicer or sharp knife. Slice tomatoes and onion into thin, even pieces.
    3 Medium Zucchini (Yellow or Green), 2 Large Tomatoes, 1 Large Red Onion
  • Add zucchini slices to a medium bowl. Drizzle with olive oil, black pepper, and Italian seasoning. Toss well to coat.
    1 tsp Black Pepper, 5 Tbsp Olive oil, 1 Tbsp Italian Seasoning
  • In a cast iron skillet or baking dish, layer zucchini slices in overlapping rows.
  • Add a thin layer of red onion rings, then a single layer of tomato slices.
  • Sprinkle ¼ cup of shredded cheddar cheese over the tomato layer.
    1 Cup Shredded Cheddar Cheese
  • Repeat layering (zucchini, onion, tomato, cheese) until all vegetables are used.
  • Top with remaining cheddar and all of the parmesan cheese.
    ½ Cup Parmesan Cheese
  • Bake uncovered for 30 minutes, or until the top is golden brown and bubbling.
  • Remove from oven and serve warm.

Notes

Amber’s Tips for Tastiness:

  • Choose medium zucchini – Smaller zucchini have firmer flesh and fewer seeds, which means less water and better texture in your casserole.
  • Layer like a lazy genius – Don’t stress about perfect rows. Even a “rustic” stack will turn out bubbly and golden. The cheese will bring it all together.
  • Use the good parm – Powdered works, but freshly grated parmesan gives a more flavorful and crispy top. It's worth it if you’ve got it.
  • Don’t skip the olive oil – It helps coat and roast the veggies evenly while locking in that herby flavor.
  • Store it smart – Leftovers keep well in an airtight container for up to 4 days. Reheat in the oven for the best texture.
  • Skip the freezer – The tomatoes and zucchini hold a lot of water, and freezing will make your cheesy layers sad and soggy.

Nutrition

Calories: 156kcalCarbohydrates: 9gProtein: 9gFat: 10gSaturated Fat: 5gPolyunsaturated Fat: 1gMonounsaturated Fat: 3gCholesterol: 25mgSodium: 760mgPotassium: 462mgFiber: 3gSugar: 5gVitamin A: 996IUVitamin C: 27mgCalcium: 275mgIron: 1mg
Keyword cast iron skillet, tomato, zucchini
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